Eubnace



w. a. ZETSCHE.

FURNACE. l PPPPP cATxoN FILED MAR.15, 1920.

'Reissued Dee. 14, 1920.

Hummm llilllill w. G. ZETSCHAE.

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l APP llllllllllllll AR. 111111 o.4 Reissued Dec. 14, 1920.

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UNITED STATES PATENT OFFICE.

WILLIAM c. za'rsc'nin', or CHICAGO, LLINoIs.

FURNACE.

Specification of Reissued'Letters 1"aten1:.v Reissud Deva 1920.

original No, 1,322,214, dated November 18,- 1919,1Sera1 No. 273,803, Ied February 28, 1919. Application for reissue filed March 15,' 1920. Serial No. 366,068.

To a-ZZ 107mm t may concern.' y

Be it knownthat I, VILLIAM G. ZE' r sGHE, a citizen of the United States, residing at Chicago, inthe county of Cools' and State of Illinois,` have invented certain new and useful Improvements in Furnaces, of which the following'is a specification.. Y

This invention has for its object to provide an improved furnace having aplurality ofr mules or hearths mounted therein foi-the heat treatment of metals, and m which the temperature ofthe several muflles or hearths may be readily regulated asv needed to producethc desired results.

The particular purpose or aim ofthe 1nvention is the provision of a furnace' ofthis character in which the series of mu'lil'es orhearths will be subjected in sequence or succession to the heat developed fromasingle sourcev of supply, although thisv may co'm prise aplurality of burners, with means for governing or controlling the temperature to which the muffles or hearth's will be subjected, as by regulating the escape between them of a portion of the productsof combustion, the heat of which discharged gases will not, therefore, .be imposed on the succeeding mufes of the group or series.

A. further object of the invention 1s the production of a furnace of this kind capable of easy'control by the operator, and which may be maintained continuously in operation with resulting economy of"` time, fuel, and labor.

Theinvention consists inlthe features of construction and combinations of parts hereinafter fully described and particularly claimed.

In the accompanying drawings illustratinv a suitable embodiment of the invention:

igure 1 is a view in side elevation of a muHle-furnace constructed in accordance with the invention; I

Fig. 2 is a plan section of the same on line 2-2 of Fig. 1;

Fig. 3 is a vertical section of the same on line 3-3 of Fig. 1; and f Fig. 4 is a plan section on the line 4 4 of Fig. 3. 1

My invention relates particularly to that class of furnaces which Iare adaptedv to be heated by gas or other iiuid fuel. To this end it comprises the housing 1 of lire-brick or other suitable material which is preferably rectangular in vertical and plan sections, the side-walls of the furnace or housing being providedat1 their upper ends with non-registering openingsQ, 2 into which thev cylindrical muftles 4, 5 and 6 spaced aparty vertically are loca-ted'inside of such housing or compartment and span the space: between its front and rear walls, the' back ends of such mufles being accommodated in cavities or recesses' in the inner face o'f the' rear wall, the front portions of the mufllesf" extending through apertures in the frorit wall of the housing and hav-ing removable plugs or 'closures 7-.1

Such muffles' being disposed at respectively different elevations and spaced away from the side-walls of the housing are adapted toy be successively' heated by the downward passage lof thehot gase'sfrom the top ofthe housing to the bottomi thereof', from which they are exhausted or discharged throughany opening 8.

At points' substantiall`yV midway between the upper mufHe 4i and the n'ezrtlower 'mufiie 5, the side-walls are provided with openings- 9', 9v adaptedv tobe more orl less closed byl adjustable plugs orlv closures 10, 170 and similar apertures, provided with like plugs orv gates 11, 11 `are located in the side-walls about midway between the intermediateV rst placed in the lowermost muffle 6 which is subjected to the least amount of heat and hence is at the lowest temperature of the three.

After having remained in such muile a proper period of time the material or body `is removed therefrom and introduced into the middle mu'Hie Where it is under the inluence of a higher degree of temperature. After having remained in such mulile for an adequate period the material vor body is taken out and deposited in the upper or hottest muiile and permitted to remain therein the required period, after which it is removed.

It will be understood that all three muflies would ordinarily be filled with the material or bodies so that all three are in service at the same time, and when the contents of the upper muliie are removed those of the in termediate one are shifted to the upper one, and also at the same time the contents of the lower muile are placed 'in the middle one. Thus, the muflies are successively emptied and refilled, hence gradually increasing the temperature of the material undergoing treatment and producing a relatively convtinuous supply of the product.

The temperature of the top mulile may be readily controlled by varying the amount of `fuel burned, that of the middle muile may be easily governed by permitting an escape or discharge through the openings 9, 9 of a portion of the products of combustion before they reach such intermediate muiile, and, in similar manner, the temperature of the lower muiile may be regulated ,or controlled bythe positions of the plugs 1l, 11 thereby opening to a more or less degree the ports l0r apertures in which they fit.

bviously, the number of muHes or,

hearths `disposed in the housing and the number of openings controlled by the plugs `or gates l0 and 11 may be changed and varied to accommodate the device to the needs of each installation. Other structural changes may be incorporated for similar reasons without departing fromv the invention as de-r fined in the appended claims.

I claim:

l. A furnace of the character described, comprising in combination, a housing, means burner means and-said discharge opening,`

and adjustable means for permitting the escape of a portion of the heated combustion gases, through the housing walls betweeny said muiiies, substantially as described.

2. A furnace of the character described, comprising in combination, a housing having connection at its upper end with a source of supply of iiuid fuel under pressure and provided in its lower end with opening for roducts of combustion, a plua discharge rality of mu es spanning the interior of the 4 housing at different elevations, there belng openings in the walls of the housing at elevations alternating with and disposed substantially in staggered relation to said openings, substantially as described.

3. A furnace of the character described, comprising in combination, a housing having in opposite walls of one end thereof fuel feed openings offset with relation to one another and an outlet at its other end for the products of combustion, a plurality of mufiies mounted at their ends in opposite walls of the housing and spanning the space between said fuel feed and discharge openings and adapted to be heated successively by the hot products of combustion as the latter flow through said housing, said mufles being spaced from each other and each having an end exposed exteriorly of the furnace, means for closing said exposed ends, and valvecontrolled ports in the walls of the housing for permitting the escape of a portion of the hot gases of combustion for regulating the temperature of the muiies, substantially as described. 

